Inconsistent datatypes problem (ORA-00932)

Question

Hi all,
Given the following two tables , located in two different schemas :
CREATE TABLE schema1.national_desc
(     ENT CHAR(18 CHAR),
     COD_MAJ CHAR(1 CHAR),
     SID_DESC_COD_ADD NUMBER(8,0),
     ID_LANG CHAR(2 CHAR) DEFAULT 'FR',
     SID_COD_ADD NUMBER(8,0),
     ID_TYP_COD_ADD CHAR(1 CHAR),
     COD_ADD CHAR(3 CHAR),
     L_DESC NCLOB,
     DAT_MAJ DATE DEFAULT SYSDATE,
     DAT_MAD DATE,
     LL_DESC NCLOB,
     CONSTRAINT pk_national_desc PRIMARY KEY (SID_DESC_COD_ADD, ID_LANG)
CREATE TABLE schema2.european_desc
(     ENT CHAR(18 CHAR),
     COD_MAJ CHAR(1 CHAR),
     SID_DESC_COD_ADD NUMBER(8,0),
     ID_LANG CHAR(2 CHAR),
     SID_COD_ADD NUMBER(8,0),
     ID_TYP_COD_ADD CHAR(1 CHAR),
     COD_ADD CHAR(3 CHAR),
     L_DESC NCLOB,
     CONSTRAINT pk_european_desc PRIMARY KEY (SID_DESC_COD_ADD, ID_LANG)
)we try this query :
SELECT
'1' origine,
sid_cod_add,
l_desc desc_cod_add,
TO_CHAR (dat_mad, 'dd/mm/yyyy') dat_mad,
TO_CHAR (dat_maj, 'dd/mm/yyyy') dat_maj
FROM
N24510
WHERE
dat_maj > '01/01/2010'
AND id_lang='FR'
UNION
SELECT
'0',
sid_cod_add,
l_desc,
NULL,
NULL
FROM
F24510
where
id_lang='FR'and Oracle complains with this error : ORA-00932.
We have tried to "cast" the L_DESC column with TO_CHAR but some column value exceeds 4000 chars.
Casting with TO_CLOB give the same first error.
Any idea ?
Stephan
Oracle 10Gr2 - 10.2.0.3.0
Linux 64bits

Answer 1

Hi ,
Thanks for your reply. We have finally find the problem :)
Instead of UNION, we perform an UNION ALL. With UNION Oracle had to check unicity
between rows containing NCLOB columns...
Hopefully, in our case UNION ALL does the trick !
Stephan